1. Field of the Invention
The present invention relates generally to aluminum-copper-magnesium based alloys and products, and more particularly to aluminum-copper-magnesium alloys and products containing silver, including those particularly suitable for aircraft structural applications requiring high strength and ductility as well as high durability and damage tolerance such as fracture toughness and fatigue resistance.
2. Description of Related Art
Aerospace applications generally require a very specific set of properties. High strength alloys are generally desired, but according to the desired intended use, other properties such as high fracture toughness or ductility, as well as good corrosion resistance may also usually be required.
Aluminum alloys containing copper, magnesium and silver are known in the art.
U.S. Pat. No. 4,772,342 describes a wrought aluminum-copper-magnesium-silver alloy including copper in an amount of 5–7 weight (wt.) percent (%), magnesium in an amount of 0.3–0.8 wt. %, silver in an amount of 0.2–1 wt. %, manganese in an amount of 0.3–1.0 wt. %, zirconium in an amount of 0.1–0.25 wt. %, vanadium in an amount of 0.05–0.15 wt. %, silicon less than 0.10 wt. %, and the balance aluminum.
U.S. Pat. No. 5,376,192 discloses a wrought aluminum alloy comprising about 2.5–5.5 wt. % copper, about 0.10–2.3 wt. % magnesium, about 0.1–1% wt. % silver, up to 0.05 wt. % titanium, and the balance aluminum, in which the amount of copper and magnesium together is maintained at less than the solid solubility limit for copper and magnesium in aluminum.
U.S. Pat. Nos. 5,630,889, 5,665,306, 5,800,927, and 5,879,475 disclose substantially vanadium-free aluminum-based alloys including about 4.85–5.3 wt. % copper, about 0.5–1 wt. % magnesium, about 0.4–0.8 wt. % manganese, about 0.2–0.8 wt. % silver, up to about 0.25 wt. % zirconium, up to about 0.1 wt. % silicon, and up to 0.1 wt. % iron, the balance aluminum, incidental elements and impurities. The alloy can be produced for use in extruded, rolled or forged products, and in a preferred embodiment, the alloy contains a Zr level of about 0.15 wt. %.